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DNA Methylation (EPIC) from the Grady Trauma Project

ABSTRACT: Childhood and cumulative exposure to trauma increases an individual's lifetime risk for psychiatric and stress-related disorders. This study evaluates DNA methylation in whole blood, with the goal of identifying associaitons between peripheral DNA methylation and psychiatric symptoms.

ORGANISM(S): Homo sapiens

PROVIDER: GSE132203 | GEO | 2019/06/06

REPOSITORIES: GEO

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Project description:While the paradigm that genetic predisposition and environmental exposures interact to shape development and function of the human brain and ultimately the risk of psychiatric disorders has drawn wide interest, the corresponding molecular mechanisms have not been elucidated yet. Here we show that a functional polymorphism altering chromatin interaction between the transcription start site and long range enhancers in the FK506 binding protein 5 (FKBP5) gene, an important regulator of the stress hormone system, increases the risk of developing stress-related psychiatric disorders in adulthood by allele-specific, childhood trauma-dependent DNA demethylation in functional glucocorticoid response elements (GREs) of FKBP5. This demethylation is linked to increased stress-dependent gene transcription followed by a long-term dysregulation of the stress hormone system and a global impact on the function of immune cells and brain areas associated with stress regulation. This first identification of molecular mechanisms of genotype-directed long-term environmental reactivity will also critically contribute to designing more effective treatment strategies for stress-related disorders. Effects of FKBP5 rs1360780 genotype x environment interaction on peripheral blood mRNA expression of GR responsive genes, as measured by gene expression arrays, were explored in 129 individuals (child abuse/risk allele carrier N = 40, child abuse/protective allele carrier N = 15; and no child abuse/risk allele carrier N = 60, no child abuse/protective allele carrier N = 14). In all 129 individuals, 1627 transcripts showed a significant correlation with plasma cortisol concentrations, suggesting their GR responsiveness. The correlation of 76 of these transcripts with cortisol plasma levels showed significant differences when stratifying by FKBP5 genotype in individuals with child abuse (Fisher z score ≥ 1.96) For these 76 transcripts, the mean absolute correlation coefficient with plasma cortisol was R = 0.23 in the risk allele carriers with child abuse, that is those exhibiting a demethylation of FKBP5 intron 7 as compared to R = 0.74 in the carriers of the protective genotype with child abuse where intron 7 methylation remains largely stable. This indicates a relative GR-resistance in the trauma exposed FKBP5 risk allele vs. protective genotype carriers. These 76 transcripts did not show a genotype-dependent difference in correlation coefficients in non-trauma exposed individuals suggesting that exposure to early trauma enhances FKBP5 genotype-dependent effect of GR sensitivity, most likely by epigenetic mechanisms. These findings suggest that the combination of FKBP5 risk allele carrier status and early trauma exposure alters the stress hormone-dependent regulation of several genes in peripheral blood cells, and might thereby enhance the reported association of early trauma with immune and inflammatory dysregulation, further promoting system-wide symptoms of stress-related disorders.

Project description:The study was aimed to identify mechanisms linked to complicated courses after severe trauma by a systems biology approach. In severe trauma, overwhelming systemic inflammation can result in adverse events and the development of complications, including sepsis. In a prospective study, RNA samples from circulating leukocytes from patients with multiple injury (injury severity score â¥ 17) were analyzed for dynamic changes in gene expression over a period of 21 days by whole genome screening. Based on their clinical presentation, patients were divided into two subgroups: patients with secondary sepsis after trauma (n=5) and patients with systemic inflammation without infection (n=5). Expression cluster were defined by correlating gene expression data with clinical outcome parameters. Using unsupervised clustering, patients with systemic inflammation only and patients with sepsis showed a distinct expression pattern and the discrimination of clinical presentation was reflected by clustering of the samples. Explorative gene set analysis revealed robust upregulation of genes related to âhemoglobin metabolism/oxygen transportâ and âpathogenic E.coli infectionâ. 10 patients with multi-system trauma (ISS â¥ 17 points) admitted to the Division of Trauma Surgery at the University Hospital Zurich were included. Whole blood from trauma patients was collected within the first 6 h after trauma (day 0) and on days 1, 2, 3, 5, 7, 10, 14, and 21. Total cellular RNA from circulating leukocytes was isolated using PaxGene Blood RNA Kit (PreAnalytix) for transcriptome profiling. RNA from blood of trauma patients was extracted and subjected to microarray analysis for comparison of longitudinal transcriptomic responses of patients. RNA samples of circulating leukocytes covering time points directly after admission (D0) and on the consecutive days (D1-D21) were subject to multifactorial microarray data analysis: Differences in dynamics of transcripts were assessed by contrasting time- and individual-resolved changes for sepsis and systemic inflammation without infection.

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DNA Methylation (EPIC) from the Grady Trauma Project

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